`Smarty::addPluginsDir()` は非推奨になったため、`Smarty::registerPlugin()` を使用するよう修正

[nanasess]

• 合わせて修正 Fixes #914
• data/smarty_extends/block.marquee.php, data/smarty_extends/modifier.numeric_emoji.php はモバイルテンプレートが廃止されたため非推奨とする

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 55.72%. Comparing base (868c729) to head (d1202bd).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #946 +/- ## ========================================== + Coverage 55.69% 55.72% +0.03% ========================================== Files 75 75 Lines 8906 8913 +7 ========================================== + Hits 4960 4967 +7 Misses 3946 3946 ``` | [Flag](https://app.codecov.io/gh/EC-CUBE/ec-cube2/pull/946/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=EC-CUBE) | Coverage Δ | | |---|---|---| | [tests](https://app.codecov.io/gh/EC-CUBE/ec-cube2/pull/946/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=EC-CUBE) | `55.72% <100.00%> (+0.03%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=EC-CUBE#carryforward-flags-in-the-pull-request-comment) to find out more.

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